Statistics Server Checks - Check Information

Check Information

8.7.1 Statistics Server Checks

The statistics server performs regular checks and issues an alert when an alert condition is fulfilled.

The following table describes the individual checks that the statistics server performs, what actions you can take when an alert is issued for a particular check, and where you can find additional information.

Note

You can see all checks on the Alerts tab of the Administration editor. The check ID is available in the Check Information screen area.

ID Name Description What to Do If an Alert Is Issued

1 Host physical memory usage

This check determines what percentage of total physical memory available on the host is used. All processes consuming memory are considered, including non-SAP HANA processes.

Note

The thresholds configured for this check determine the color of the bar displaying memory usage values on the Overview screen of the Administration editor.

Investigate memory usage. Which services are consuming a lot of memory? Are there any underlying performance-related issues, for example, high-load operations in progress, suboptimal SQL processing?

You can investigate memory usage in the Administration editor on the Overview tab and the Landscape tab.

The Performance tab is a good starting point for performance

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ID Name Description What to Do If an Alert Is Issued

2 Disk usage This check determines what

percentage of space on each disk containing data, log, backup files, and trace files is currently used.

This includes space used by non-SAP HANA files.

To ensure that the database can always be restored to its most recent committed state and to avoid a disk-full event, there must always be enough space on disk for data and log files.

Note

The thresholds configured for this check determine the color of the bar displaying usage values on the Overview screen of the Administration editor.

Investigate disk space usage. Which services are consuming a lot of disk space? Can space be freed up, for example, through volume

shrinkage, log file deletion? Is it necessary to add additional disk space?

You can investigate disk space usage in the Administration editor on the Overview tab and the Volumes tab.

3 Inactive services This check determines whether or not any of the database's services (nameserver, indexserver, preprocessor, and so on) are currently inactive.

For example, if a host in a distributed system failed and a standby host took over, the services of the failed host remain inactive even after the host is reachable again. In this case, you need to restart the services manually.

Investigate why services are inactive, for example, by checking the service's trace files.

You can restart inactive services in the Administration editor on the Landscape tab.

For more information, see:

● Stopping and Starting Database Services [page 41]

● Working with Diagnosis Files [page 349]

4 Restarted services This check determines whether or not any of the database's services (nameserver, indexserver,

preprocessor, and so on) have been restarted since the last time the check was performed.

Investigate why the service had to restarted, for example, by checking the service's trace files.

For more information, see:

● Stopping and Starting Database Services [page 41]

● Working with Diagnosis Files [page 349]

5 Host CPU usage This check determines the percentage CPU idle time on the host and therefore whether or not CPU resources are running low.

Investigate CPU usage. Which services are consuming a lot of CPU resources?

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ID Name Description What to Do If an Alert Is Issued

Note

The thresholds configured for this check determine the color of the bar displaying CPU usage values on the Overview screen of the Administration editor.

You can investigate CPU usage in the Administration editor on the Overview tab and the Landscape tab.

This check determines whether or not the parameter active in the mergedog section(s) of system configuration files is yes.

mergedog is the system process that periodically checks column tables to determine whether or not a delta merge operation needs to be executed.

Set the parameter active in the mergedog section(s) of configuration files to yes.

For more information, see:

● Changing System Properties [page 44]

● The Delta Merge Operation [page 157]

12 Memory usage of name server

This check determines what percentage of allocated shared memory is being used by the nameserver process on a host.

Increase the shared memory size of the name server. In the topology section of the nameserver.ini file, increase the value of the size parameter.

For more information, see Changing System Properties [page 44]

16 Lock wait timeout configuration

This check determines whether the lock_waittimeout parameter in the transaction section of the

indexserver.ini file is between 100,000 and 7,200,000.

In the transaction section of the indexserver.ini file, set the lock_wait_timeout parameter to a value between 100,000 and 7,200,000 for the System layer.

For more information, see Changing System Properties [page 44]

17 Record count of non-partitioned column-store tables

This check determines the number of records in non-partitioned column tables.

A non-partitioned table cannot store more than 2,000,000,000 (2 billion) rows. It is possible to

Current table size is not critical.

Consider partitioning the table only if you expect the table to grow significantly.

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ID Name Description What to Do If an Alert Is Issued

overcome this limit by distributing

the table across several partitions.

Recommendation

Change the threshold values for this alert to 1500,000,000 (low priority alert), 1,800,000,000 (medium priority alert), and 1900,000,000 (high priority alert).

For more information, see:

● Table Partitioning in the SAP HANA Database [page 193]

● Configuring Check Thresholds [page 124]

19 Record count of delta storage of column-store tables

This check determines the number of records in the delta storage of column tables.

It is important that the delta storage of a table does not become

excessively large and is regularly merged with the main storage.

The delta merge operation is triggered in different ways depending on your system configuration.

Investigate the delta merge history to find out when the last delta merge operation was supposed to happen and why it did not. Consider merging the table delta manually.

For more information, see:

● Monitoring Delta Merge History [page 164]

● The Delta Merge Operation [page 157]

● Performing a Manual Delta Merge Operation [page 166]

20 Table growth of non-partitioned column-store tables

This check determines the growth rate of non-partitioned columns tables.

If table growth is significant, consider partitioning the table.

For more information, see Table Partitioning in the SAP HANA Database [page 193]

21 Internal event This check determines whether or not there are any internal database problems.

Resolve the event and mark it as resolved by executing the following SQL statement: ALTER SYSTEM SET EVENT HANDLED <:event>.

22 Notification of all alerts This check determines whether or not there have been any alerts since the last check and if so, sends a

This check determines whether or not there have been any medium

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ID Name Description What to Do If an Alert Is Issued and high priority alerts since the last

check and if so, sends a summary e-mail to specified recipients.

24 Notification of high priority alerts

This check determines whether or not there have been any high priority alerts since the last check and if so, sends a summary e-mail to specified recipients.

25 Open connections This check determines what percentage of the maximum number of permitted SQL connections are open.

The maximum number of permitted connections is configured in the session section of the

indexserver.ini file.

Investigate why the maximum number of permitted open connections is being approached.

You can cancel sessions on the Performance Sessions tab.

For more information, refer to the monitoring view M_CONNECTIONS.

Note

It is possible to reserve a certain number of connections so that administrators (that is, users with the system privilege SESSION ADMIN) can always access the system, even if the maximum number of

connections has been reached.

For more information, see Reserving Connections for Administrators [page 48].

26 Unassigned volumes This check identifies volumes that are not assigned a service.

Investigate why the volume is not assigned a service. For example, the assigned service is not active, the removal of a host failed, or the removal of a service was performed incorrectly.

For more information, see:

● About Persistent Data Storage in the SAP HANA Database [page 134]

● Monitoring Disk Space [page 132]

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ID Name Description What to Do If an Alert Is Issued 27 Record count of

column-store table partitions

This check determines the number of records in column table

partitions.

A table partition cannot store more than 2,000,000,000 (2 billion) rows.

Consider re-splitting the table.

For more information, seeTable Partitioning in the SAP HANA Database [page 193]

28 Most recent savepoint operation

This check determines how long ago the last savepoint was defined, that is, how long ago a complete, consistent image of the database was persisted to disk.

The frequency at which savepoints are defined can be configured in the persistence section of the

global.ini file (every 5 minutes by default). Savepoints are also triggered automatically by a number of other operations such as data backup, and database

shutdown and restart.

Investigate why there was a delay defining the last savepoint and consider triggering the operation manually. To do so execute SQL statement ALTER SYSTEM SAVEPOINT.

29 Size of delta storage of column-store tables

This check determines the size of the delta storage of column tables.

It is important that the delta storage of a table does not become

excessively large and is regularly merged with the main storage.

The delta merge operation is triggered in different ways depending on your system configuration.

Investigate the delta merge history to find out when the last delta merge operation was supposed to happen and why it did not. Consider merging the table delta manually.

For more information, see:

● Monitoring Delta Merge History [page 164]

● Monitoring Delta Merge Processing in Column Store Tables [page 166]

● Performing a Manual Delta Merge Operation [page 166]

30 Internal disk-full event This check determines whether or not the disks to which data and log files are written are full.

A disk-full event causes your database to stop and must be resolved.

Resolve the disk-full event.

For more information, see:

● Resolving Disk-Full Events [page 137]

● About Persistent Data Storage in the SAP HANA Database [page 134]

31 License expiry This check determines how many days until your license expires.

Obtain a valid license and install it.

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ID Name Description What to Do If an Alert Is Issued

Once your license expires, you can no longer use the system, except to install a new license.

For more information, see Installing Permanent Licenses [page 54]

32 Log mode OVERWRITE This check determines whether or not the database is running in log mode OVERWRITE.

Log mode OVERWRITE does not support point-in-recovery (only recovery to a data backup) and is not recommended for productive systems.

If you need point-in-time recovery, reconfigure your system to log mode NORMAL.

For more information, see Log Backup Options [page 235]

33 Log mode LEGACY This check determines whether or not the database is running in log mode LEGACY.

Log mode LEGACY is not recommended for productive systems. If a point-in-time recoverable system is needed the database must run in log mode NORMAL.

If you need point-in-time recovery, reconfigure your system to log mode NORMAL.

For more information, see Log Backup Options [page 235]

34 Unavailable volumes This check determines whether or not all volumes are available so that a backup can be performed.

Investigate why the volume is not available, for example, is the associated service active?

For more information, see:

● Stopping and Starting Database Services [page 41]

● About Persistent Data Storage in the SAP HANA Database [page 134]

35 Existence of data backup This check determines whether or not a data backup exists.

To make your database

recoverable, perform a data backup.

For more information, see Backing Up the SAP HANA Database [page 247]

36 Status of most recent data backup

This check determines whether or not the most recent data backup was successful.

Investigate why the last data backup was not successful, resolve the problem, and perform a new data backup as soon as possible.

For more information, see Backing Up the SAP HANA Database [page 247]

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ID Name Description What to Do If an Alert Is Issued 37 Age of most recent data

backup

This check determines the age of the most recent successful data backup.

Perform a data backup as soon as possible.

For more information, see Backing Up the SAP HANA Database [page 247]

38 Status of most recent log backups

This check determines whether or not the most recent log backups were successful.

Investigate why the log backup was not successful and resolve the problem.

For more information, see About SAP HANA Database Backup [page 229]

39 Long-running statements This check determines whether or not there are any SQL statements that have been running for a long time.

The table

HOST_LONG_RUNNING_STATEME NTS (_SYS_STATISTICS) provides you with more detailed information about individual statements.

40 Total memory usage of column-store tables

This check determines what percentage of the effective memory allocation limit is being consumed by a column table as a whole (that is, the cumulative size of all of a table's columns and internal structures).

Consider partitioning (or re-partitioning) the table or moving it to another host.

● Table Partitioning in the SAP HANA Database [page 193]

● Redistribution of Tables in a Distributed SAP HANA System [page 207]

● Memory Usage of Column and Row Tables [page 141]

● Memory Management in the Column Store [page 154]

41 In-memory DataStore activation

This check determines whether or not there is a problem with the activation of an in-memory DataStore object.

For detailed information, refer to table

GLOBAL_DEC_EXTRACTOR_STAT US (_SYS_STATISTICS).

For more information, see SAP Note 1665553.

42 Long-running cursors This check finds cursors that have been open for more than the specified threshold values.

Close the cursor in the application, or kill the connection by executing the SQL statement ALTER SYSTEM DISCONNECT SESSION

<LOGICAL_CONNECTION_ID>.

For more information, see the table HOST_LONG_IDLE_CURSOR (_SYS_STATISTICS)

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ID Name Description What to Do If an Alert Is Issued 43 Memory usage of services This check determines what

percentage of its effective allocation limit a process is using.

Investigate why the process is consuming a lot of memory.

You can monitor the memory usage of services in the Administration editor on the Landscape tab. The Performance tab is a good starting point for analyzing underlying

44 Licensed memory usage This check determines what percentage of licensed memory is used.

Increase the licensed amount of main memory.

For more information, see Installing Permanent Licenses [page 54]

45 Memory usage of main storage of column-store tables

This check determines what percentage of the effective memory allocation limit is being consumed the main storage of a column table.

Consider partitioning (or re-partitioning) the table or moving it to another host.

● Table Partitioning in the SAP HANA Database [page 193]

● Redistribution of Tables in a Distributed SAP HANA System [page 207]

● Memory Usage of Column and Row Tables [page 141]

● Memory Management in the Column Store [page 154]

46 Runtime dump files This check determines whether or not new runtime dump files have been generated in the trace directory of the system. These contain information about, for example, build, loaded modules, running threads, CPU, and so on.

SAP Support may want to examine these files for problem analysis.

Check the contents of dump files.

You can access them on the Diagnosis Files (filter by rtedump).

For more information, see Working with Diagnosis Files [page 349]

47 Long-running serializable transactions

This checks determines whether or not there are any long-running serializable transactions.

Close the serializable transaction in the application or kill the connection by executing the following SQL statement: ALTER SYSTEM

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ID Name Description What to Do If an Alert Is Issued DISCONNECT SESSION

<LOGICAL_CONNECTION_ID>.

For more information, see the table HOST_LONG_SERIALIZABLE_TRAN SACTION (_SYS_STATISTICS).

48 Long-running uncommitted write transactions

This check determines whether or not there are any uncommitted transactions. Such transactions can impact the performance of the database.

Close the uncommitted transaction in the application or kill the

connection by executing the following SQL statement: ALTER SYSTEM DISCONNECT SESSION

<LOGICAL_CONNECTION_ID>.

For more information, see the table HOST_LONG_UNCOMMITTED_WRI TE_TRANSACTION

(_SYS_STATISTICS).

49 Long-running blocking situations

This check determines whether or not there are any blocked

transactions.

Review the blocking and blocked transactions, for example, on the

Performance Threads , and if appropriate cancel one of them.

For more information, see Monitoring System Performance [page 125]

50 Number of diagnosis files This check determines the number of diagnosis files written by the system. A unusually large number of files can indicate a problem with the database (for example, problem with trace file rotation or a high number of crashes).

Check the diagnosis files. You can access them on the Diagnosis Files.

For more information, see Working with Diagnosis Files [page 349]

51 Size of diagnosis files This check determines the size of individual diagnosis files. An unusually large file can indicate a problem with the database.

Check the diagnosis file in question.

You can access them on the Diagnosis Files.

For more information, see Working with Diagnosis Files [page 349]

52 Crash dump files This check determines whether or not new crashdump files have been generated in the trace directory of the system. SAP Support may want to examine these files for problem analysis.

Check the contents of crash dump files. You can access them on the Diagnosis Files (filter by

crashdump).

For more information, see Working with Diagnosis Files [page 349]

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ID Name Description What to Do If an Alert Is Issued 53 Page dump files This check determines whether or

not new page dump files have been generated in the trace directory of the system. SAP Support may want to examine these files for problem

In document SAP_HANA_Administration_Guide_en[1].pdf (Page 112-123)